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A223600
Petersen graph (8,2) coloring a rectangular array: number of 2 X n 0..15 arrays where 0..15 label nodes of a graph with edges 0,1 0,8 8,14 8,10 1,2 1,9 9,15 9,11 2,3 2,10 10,12 3,4 3,11 11,13 4,5 4,12 12,14 5,6 5,13 13,15 6,7 6,14 7,0 7,15 and every array movement to a horizontal, diagonal or antidiagonal neighbor moves along an edge of this graph.
1
256, 256, 1504, 6736, 32768, 156592, 755200, 3643024, 17608064, 85179184, 412367104, 1997306896, 9677417600, 46900761520, 227339596288, 1102103488912, 5343259128704, 25906912147504, 125615423519488, 609091866864400
OFFSET
1,1
COMMENTS
Row 2 of A223599.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) + 3*a(n-2) - 42*a(n-3) - 8*a(n-4) + 48*a(n-5) for n>6.
Empirical g.f.: 16*x*(16 - 80*x - 50*x^2 + 481*x^3 + 40*x^4 - 456*x^5) / ((1 + 2*x)*(1 - 8*x + 13*x^2 + 16*x^3 - 24*x^4)). - Colin Barker, Aug 21 2018
EXAMPLE
Some solutions for n=3:
..2..3..4...11..3..4....0..8.14...15..7..0...15..9..1....3..4..3....9.15..7
.11..3..2....4..3..4...10..8.10....0..7..0...11..9.15....5..4..5...13.15..9
CROSSREFS
Cf. A223599.
Sequence in context: A186474 A093861 A248776 * A217848 A044872 A044979
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 23 2013
STATUS
approved